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Kok Dick Shun , Louis. / Thesis (Ph.D.)--Chinese University of Honbg Kong, 1997. / Includes bibliographical references (p. i-xiii). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

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A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, in fulfilment of the requirements for the Degree of Master of Science (Medicine) / Classical epithelio-mesenchymal interactions are said to result in root development. These interactions may be regulated by a number of growth factors. Fibroblast growth factors (FGF’s), members of a highly conserved family of polypeptides, the heparin binding growth factors (HBGF’s) are known to play a crucial role during the development of certain vertebrate organs, including the tooth. Previously, FGF-2, 3, 4, and 8 have been shown to play a role in crown development. The aim of this study was therefore to elucidate the spatial and temporal expression of FGF-2 in the developing root. Parasagittal sections of the maxillary and mandibular arches of six age groups of post-natal mice (days 9, 10, 12, 16, 20 and 24) were cut and the developing roots of the incisor and molar teeth identified. Immunocytochemistry utilizing anti-FGF-2 was performed on sections of teeth from all stages using the strept-avidin biotin technique. Appropriate positive, negative and absorption controls were performed to ensure the specificity of the antibody. FGF-2 was immunolocalized in the cytoplasm and nuclei of the odontoblasts, fibroblasts of the periodontal ligament and pulp chamber, as well as in the osteoblasts surrounding developing bone at all the stages examined. Intense staining for FGF-2 was observed in differentiating odontoblasts at the apical end and the furcation zone of the developing root. FGF-2 localization was also observed in the cytoplasm of the ameloblasts on days 9, 10 and 12 and in cementoblasts on day 16, 20 and 24. The spatio-temporal expression pattern of FGF-2 in the developing mouse tooth root suggests that FGF-2 with other signaling molecules previously reported such as bone morphogenetic proteins-2, 3 and 7 (BMP-2, 3 and 7) participate in the signaling network during the tooth root development. / IT2018

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<p>Heparan sulfate (HS) belongs to the glycosaminoglycan family of polysaccharides and is found attached to protein cores on cell surfaces and in the extracellular matrix. The HS backbone consists of alternating hexuronic acid and glucosamine units and undergoes a number of modification reactions creating HS chains with alternating highly and low modified domains, where high degree of modification correlates with high negative charge. Fibroblast growth factors (FGFs) and their receptors (FRs) both bind to HS, which affect formation of the FGF–FR complexes on the cell surfaces. Activated FRs can trigger several intracellular signaling pathways leading thereby to diverse cellular responses. </p><p>Work presented in this thesis focuses on the effect of HS and its structures on FGF–FR complex formation and FGF-induced signaling. Studies with short, highly modified oligosaccharides and FGF1 and 2 combined with FR1c, 2c, 3c or 4 showed a correlation between the overall degree of modification and amount/stability of FGF–FR complexes. Our findings imply that several HS structures, differently modified but with the same negative charge density are equal in their ability to support complex formation. Co-application of oligosaccharides with FGF2 to HS-deficient cells and investigation of the thereby induced cell signaling confirmed our findings with a cell-free system. The oligosaccharide with the highest modification degree displayed the biggest impact on cell signaling, which was FGF2 concentration dependent. Studies with long HS polysaccharides with preserved high and low modified domains suggest that the proportion between these two types of domains and also the structure of the low modified domains are of importance for the FGF–HS–FR complex formation and cell activation capacity. </p><p>This work illuminates several aspects in how HS structure influences the interplay between FGFs and FRs and contributes to the understanding of what factors affect a cell’s response following FGF stimulation.</p>

Heparan sulfate (HS) belongs to the glycosaminoglycan family of polysaccharides and is found attached to protein cores on cell surfaces and in the extracellular matrix. The HS backbone consists of alternating hexuronic acid and glucosamine units and undergoes a number of modification reactions creating HS chains with alternating highly and low modified domains, where high degree of modification correlates with high negative charge. Fibroblast growth factors (FGFs) and their receptors (FRs) both bind to HS, which affect formation of the FGF–FR complexes on the cell surfaces. Activated FRs can trigger several intracellular signaling pathways leading thereby to diverse cellular responses. Work presented in this thesis focuses on the effect of HS and its structures on FGF–FR complex formation and FGF-induced signaling. Studies with short, highly modified oligosaccharides and FGF1 and 2 combined with FR1c, 2c, 3c or 4 showed a correlation between the overall degree of modification and amount/stability of FGF–FR complexes. Our findings imply that several HS structures, differently modified but with the same negative charge density are equal in their ability to support complex formation. Co-application of oligosaccharides with FGF2 to HS-deficient cells and investigation of the thereby induced cell signaling confirmed our findings with a cell-free system. The oligosaccharide with the highest modification degree displayed the biggest impact on cell signaling, which was FGF2 concentration dependent. Studies with long HS polysaccharides with preserved high and low modified domains suggest that the proportion between these two types of domains and also the structure of the low modified domains are of importance for the FGF–HS–FR complex formation and cell activation capacity. This work illuminates several aspects in how HS structure influences the interplay between FGFs and FRs and contributes to the understanding of what factors affect a cell’s response following FGF stimulation.